1. Field of the Invention
The present invention relates to a telephone and data network for mobile subscribers comprising radio concentrators locally distributed in the overall area of a radio network, which can communicate by way of a radio with the mobile subscribers and comprising radio exchange offices associated with one or more concentrators connected to the public telephone system and, where applicable, for the purpose of data transmission, between mobile subscribers and subscribers to the public data network, to the teleprinter and data network.
2. Description of the Prior Art
If in a network for mobile subscribers a stationary or mobile subscriber dials a mobile subscriber's station, care must be taken that the call will reach the dialed mobile subscriber's station even if it is located in the area of a radio exchange office other than its home radio exchange office. It is known, for example from the German published application No. 2,040,028, to assign the call numbers of all mobile subscriber stations along with the area code of that temporary exchange office in whose area the mobile subscriber happens to be to one central telephone or call number memory which can be interrogated indirectly from each telephone exchange. If, in fact, a call is received at a temporary exchange office which is directed to a mobile subscriber, a connection is established automatically to the central call number memory and the latter is interrogated as to whether the number called is stored there. If the number is so stored, the area code stored for the number called is transmitted back to the interrogating temporary exchange and the latter establishes a connection. One disadvantage of this known prior method is the fact that all incoming calls directed to a mobile subscriber must be transmitted to the central call number memory. If this call number memory fails due to some defect, a connection to a mobile subscriber is no longer possible. Moreover, it is complicated, even in case of a connection within the area of the same radio exchange office to first inquire of the call number memory.